fn main(){
    let bool_value: bool = true;
    let char_value: char = 'a';
    let i8_value: i8 = -128;
    let u8_value: u8 = 255;
    let i32_value: i32 = -1;
    let u32_value: u32 = 1;
    let i64_value: i64 = -1;
    let float_pi: f32 = 3.14;
    let double_e: f64 = 2.71;

    println!("bool_value: {}", bool_value);
    println!("char_value: {}", char_value);
    println!("i8_value: {}", i8_value);
    println!("u8_value: {}", u8_value);
    println!("i32_value: {}", i32_value);
    println!("u32_value: {}", u32_value);
    println!("i64_value: {}", i64_value);
    println!("float_pi: {}", float_pi);
    println!("double_e: {}", double_e);
}